This invention relates to tire and rim assemblies for aircraft and especially to safety devices for preventing sudden failure or explosion of the tire due to high temperatures. Usually these high temperatures are generated during braking and especially during a rejected take-off situation where the maximum braking is required. The high temperatures cause dangerously high pressures to develop in the tire and if this pressure is not released the tire will burst endangering personnel in the area and damaging parts of the aircraft adjacent the tire.
Heretofore holes have been drilled in the wheel rim and plugs of eutectic material screwed in the holes. When the temperature of the rim at the plugs reached a predetermined level, the eutectic material would melt and release the air pressure. The placement of plugs in the rim has been limited to those areas not covered by the bead of the tire. Usually the best location on the rim for the plugs of eutectic material is where the temperatures are the highest; however, these parts of the rim are often covered by the tire and it is therefore not possible to obtain the safety desired. Another problem is that the wall of the wheel rims must be of a minimum thickness to retain the plugs and the wall of a rim may have to be made thicker and heavier where the plugs are located. To balance the wheel, this area of greater thickness must then extend completely around the rim and therefore further increase the weight and cost of the rim. The additional weight is also undesirable for aircraft where every additional pound represents a pound reduction in pay load and extra power requirements.
In many aircraft brake installations used heretofore the plugs of eutectic material have been located in positions where it is necessary to remove the wheel in order to replace the plugs. This is time consuming and costly in aircraft operations where the time element is so critical.